JPH10166724A - Multicolor recording material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve color reproducibility and color fastness by making a first recording layer form a latent image by mixing photochromic elements by heat and develop color by light, and a second recording layer form a latent image by mixing photo-decolorizing elements by heat and decolorize by light. SOLUTION: A recording material that can perform full-color recording used in a non-transfer type thermal recording system using a thermal head, is formed by providing the first and the second recording layer on a support body. In this case, the first recording layer forms a latent image by mixing photochromic elements by heat and develop colors. The second recording layer forms a latent image by mixing photo-decolorizing elements by heat and decolorizes by light. As photochromic elements, compounds that are dissolved by light and elements that colors by reacting with the decomposition product thereof are used and as decolorizing elements, a photo radical generating agent and a pigment that is decolorized by free radicals generated by the photo radical generating agent are used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multicolor recording material provided with a recording layer that develops a color by heating and then irradiating light and a recording layer that decolors by heating and then irradiating light.

[0002]

2. Description of the Related Art In recent years, with the rapid development of the information industry, there is an increasing demand for obtaining a color hard copy easily and in a short time from a terminal such as a computer or a facsimile. Under these circumstances, various types of color hard copies have been marketed as products.However, a non-transfer type thermal recording method using a thermal head is a system that can obtain high-quality images with a simple recording apparatus. It has attracted attention because it has features such as high reliability, no noise at the time of recording, no maintenance, no running cost, and no waste material accompanying recording.

[0003] Various studies have been made to realize multi-color recording by a thermal recording method by taking advantage of this advantage.
In order to achieve full color by this method, it is necessary to independently develop recording layers having different thermal sensitivities.

As one of the means, Japanese Patent Application Laid-Open No. 61-40 / 1986
No. 192, using a diazo compound having a property of deactivating a coupling ability with a coupling agent when decomposed by light, each of the coloring layers is independently formed by decomposing the diazo compound remaining after heat recording with light. There has been proposed a heat-sensitive recording material of a type in which a color is formed to perform multicoloring (hereinafter, the heat-sensitive recording material is simply referred to as a recording material). However, since this recording material uses a diazo compound having poor thermal stability, it has a serious problem that the long-term storage decomposes the diazo compound and lowers the maximum color density.

A full-color heat-sensitive material without using a diazo compound having poor thermal stability is disclosed in
No. 43252, a multicolor recording material provided with a light-sensitive and heat-sensitive coloring layer comprising a microcapsule containing an oxidative coloring type leuco dye and a photo-oxidizing agent and a reducing agent, and a heat-sensitive coloring layer comprising an electron-donating leuco dye and an electron-accepting compound. Has been proposed. However, this recording material mixed the reducing agent outside the microcapsule with the photooxidant inside the microcapsule by thermal recording and stopped the color development,
This is a method in which the unheated part is colored by exposing the entire surface.Because the oxidative coloring type leuco dye and the photo-oxidizing agent are mixed from the beginning, they are exposed to room light or sunlight during storage or during long-term storage. There was a major drawback in that the photooxidant was gradually decomposed, resulting in fogging.

[0006] Japanese Patent Application Laid-Open No. 2-190383,
No. 190385, 2-190386 and the like utilize the property that an organic boron compound salt of a cationic dye such as a cyanine dye or a xanthene dye is decolorized by irradiating light in an absorption region of the dye. A heat-sensitive recording material for forming an image is described. This is because the organic boron compound is decomposed into a compound that does not cause photobleaching by mixing a compound capable of decomposing the organic boron compound with the organic boron compound in the heated print portion, and then the non-heated portion is irradiated by light irradiation. The recorded image is obtained by erasing the color. However, in such a recording material, the light resistance of the cationic dye used is poor, the solubility of the dye in a salt form in an organic solvent is low, the cost of the dye is high, and the absorption of the dye is high. Since the color is erased by irradiating light of the wavelength of the region, the color is easily erased even with room light, and there are various problems such as difficulty in handling in a bright room.

Further, as described in Japanese Patent Application Laid-Open No. 2-190385, the range of hues that can be reproduced by a light-fixable diazo compound is limited, which restricts full color printing. Also, Japanese Patent Application Laid-Open No. 2-190383
As can be seen from JP-A Nos. 2-190385 and 2-190386, the selection range of the hue of the organic boron compound salt of the cationic dye is also narrow, and it is impossible to achieve full color only by using the decoloring type element using the same. It was difficult.

[0008]

The problem to be solved by the present invention is to solve the above-mentioned problems of the prior art, and has a wide range of choice of color materials, good hue and fastness. Color materials that provide excellent color reproduction and image fastness, and have excellent storage stability without lowering the maximum color density or fogging even after long-term storage. It is to provide a recording material that can be recorded.

[0009]

The problem to be solved by the present invention is to form a first recording layer containing a photochromic element and a second recording layer containing a photodecolorable element on a support. In the multicolor recording material provided, in the first recording layer, the light-coloring elements are mixed by heat to form a latent image, and the latent image is colored by light, and the second recording layer is The multicolor recording material is characterized in that the light decoloring element is mixed by heat to form a latent image, and the latent image or a portion other than the latent image is decolorized by light.

Hereinafter, the present invention will be described in detail.

The present inventors have conducted intensive studies on a thermosensitive coloring system which does not use a diazo compound having poor thermal stability and has improved fogging during storage. As a result, a latent image is formed by mixing with heat, A heat-sensitive material composed of a light-color-forming element that forms a latent image by light; and a light-quenching element that is mixed by heat to form a latent image, and the latent image or a part other than the latent image is decolorized by light. It has been found that a heat-sensitive material composed of color elements is excellent in storage stability without lowering of the maximum color density or occurrence of fogging even during long-term storage.
Since a heat-sensitive material that adjusts the color density by a difference in heat energy generally has poor raw storage stability, raw storage stability is a very important performance item for a heat-sensitive material. Therefore,
It would be very effective if a multicolor heat-sensitive material could be made using the photochromic element or photobleachable element having excellent storage stability.

In order to perform multicolor recording in which a desired hue can be recorded at will, it is necessary to incorporate a plurality of recording elements for recording in different hues on a support and record each recording element independently. There is. In the light-coloring element discovered by the present inventors, at the same time as the heated portion develops color by light irradiation after thermal recording, the photosensitive substance in the light-coloring element is decomposed even in the non-heated portion, but the color is formed because it is not in a mixed state. The reaction does not proceed. That is, fixing is performed simultaneously with color development by light irradiation. In the light decoloring element of the present invention, the photosensitive material in the light decoloring element is also decomposed in the non-heated part or the heated part at the same time as the heated part or the non-heated part is decolorized by light irradiation after thermal recording. However, the decoloring reaction does not proceed due to the presence of a substance that is not in a mixed state or that suppresses the function of the decolorized product in decoloring. That is, fixing is performed simultaneously with decoloring by light irradiation. Using this property,
In principle, multicolor recording becomes possible. Considering light room handling, it is desirable to fix using ultraviolet light.However, separating multiple light-coloring elements with different ultraviolet light involves many restrictions, and is the minimum necessary for full color It is practical to fix two colors. The present inventors have conducted intensive studies, and as a result, by combining a light-coloring element and a light-decoloring element, a heat-sensitive material having excellent storage stability, a wider range of color material choices, and a 3D material required for full-color recording. The present inventors have found that it is easy to independently record colors, and arrived at the present invention.

As the light-emitting element used in the present invention, any element can be used as long as it is mixed by heat to form a latent image and the latent image is colored by light. , A compound which is decomposed by light and reacts with a decomposition product thereof to form a color.

Compounds that decompose by light include ultraviolet light,
Any compound that decomposes by light such as visible light or infrared light may be used, for example, a compound called a photo-free radical generator,
And azide compounds. Examples of the photo-free radical generator include JP-B-62-39728 and JP-B-63-2793.
No. 099, 2,4,6-triarylimidazole dimer compound; U.S. Pat. No. 3,282,693, 2-azidobenzooxadiazole, azide compound such as benzoylazide, 2-azidobenzimidazole Pyridium compounds such as 3'-ethyl-1-methoxy-2-pyridothiocyanine perchlorate and 1-methoxy-2-methylpyridinium-p-toluenesulfonate described in U.S. Pat. No. 3,615,568; Bromosuccinimide, tribromomethylphenylsulfone, diphenyliodonium salt, 2-trichloromethyl-5- (p-butoxystyryl) -1,3,4-oxadiazole, 2,6-bis (trichloromethyl) -4-
Organic halogen compounds such as (p-methoxyphenyl) -s-triazine, carbonyl compounds such as benzophenone, thioxanthone, and benzoin ether; azo compounds such as azobisisobutyronitrile; organic sulfur compounds such as alkyl disulfide and mercaptan; triphenyl And phosphorus-based compounds such as phosphine.

A compound decomposed by light is decomposed by light, and then reacts with the decomposition product to form a color by reacting with a color-forming element to form a dye. The compound may be a part of the compound, or may be changed to a compound different from the dye only by participating in the dye formation reaction. It is determined by the combination of a compound that decomposes by light and an element that develops a color by reacting with its decomposition product, but is selected in consideration of the production efficiency, color tone, robustness, extinction coefficient, etc. of the dye produced by the reaction. .

Various reactions can be used as the reaction according to the present invention for producing a color-forming dye by reacting with a photodegradable compound and its decomposition product, but the following reaction shown in the following "Chemical Formula 1" is preferable. There are three types.

[0017]

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(In the above reaction formula, A represents a photodegradable compound, A 'represents a photolysis product, and B, C, D
Represents an element which develops a color in response to A '. D ', B
-C and AC represent the generated coloring pigment. B 'is a form in which B is changed by the reaction with A'. The above reaction formulas are schematic representations of each type,
It is useful for understanding what the generated dye skeleton is derived from. In the above reaction formula, the element which forms a color by reacting with A 'is described as being composed of a single compound (types 1 and 3) and composed of two types of compounds (type 2). It may consist of more than one type. Also,
Auxiliary components (eg, bases and acids) that promote the dye-forming reaction are not described, but may be included in the photochromic element. That is, in the case of type 1, the photodegradation product of A and the reaction of D generate D by oxidation, decomposition, and the like, thereby forming a coloring pigment. The basic skeleton of the coloring pigment is derived from D.

In the case of the second type, after one of the coloring elements B is activated by a certain change (for example, oxidation or decomposition) by the reaction with A ', the C of the other coloring elements is activated.
Reacts (for example, a coupling reaction or the like) to generate a coloring dye, and the basic skeleton of the coloring dye is derived from B and C.

In the case of the type 3, the A 'and C react with each other (for example, a coupling reaction) to form a coloring dye, but unlike the type 1, the basic skeleton of the coloring dye formed is A and Derived from C.

As an example of the type 1, the compound decomposed by light is a photoradical generator such as a 2,4,6-triarylimidazole dimer compound or an organic halogen compound, and the decomposition product is There are cases where the reacting element is a leuco dye. In this case, the decomposition products generated by light irradiation are imidazolyl free radicals and halogen free radicals,
Has strong oxidizing power. Utilizing the oxidizing power, for example, a leuco dye can be oxidized into a coloring dye. As leuco dyes that can be used, for example, those described in U.S. Pat. No. 3,445,234 can be used, and typical structures include the following.

1) aminotriarylmethane 2) aminoxanthene 3) aminothioxanthene 4) amino-9,10-dihydroacridine 5) aminophenoxazine 6) aminophenothiazine 7) aminodihydrophenazine 8) aminodiphenylmethane 9) leucoin Damine 10) aminohydrocinnamic acid (cyanomethane, leucometine) 11) hydrazine 12) leucoin digoid dye 13) aminodihydroanthraquinone 14) 4,4'-biphenol 15) 2- (p-hydroxyphenyl) -4,5-diphenylimidazole 16) Phenethylaniline Specific examples of the compound include leuco crystal violet, tris (4-dimethylamino-o-tolyl) methane, bis (4-dimethylamino-o-tolyl) phenylmethane, Bis (4-dimethylamino-o-tolyl) thienylmethane, 2- (2-chlorophenyl) -amino-6
-N, N-dibutylamino-9- (2-methoxycarbonyl) phenylxanthene, 2-N, N-dibenzylamino-6-N, N-diethylamino-9- (2-methoxycarbonyl) phenylxanthene, benzo [ a] -6
-N, N-diethylamino-9- (2-methoxycarbonyl) phenylxanthene, benzoylleucomethylene blue, benzoyl-3,7-diethylaminophenoxazine, benzoyl-3,7-diethylamino-9-phenyldihydrophenazine, 6,6 ′ -Di-t-butyl-p, p'-bio-cresol;

Among them, preferred leuco dyes are triarylmethane leuco dyes such as tris (4-dimethylamino-o-tolyl) methane and benzoylleucomethylene blue, benzoyl-3,7-diethylaminophenoxazine, benzoyl-3. And acylated leucoazine dyes such as 7,7-diethylamino-9-phenyldihydrophenazine. Also,
Examples of the photo-free radical generator used in combination with the above-described leuco dye include 2,4,6-triarylimidazole dimer compound, tribromomethylphenyl sulfone,
Organic halogen compounds such as 6-bis (trichloromethyl) -4- (p-methoxyphenyl) -s-triazine can be mentioned. These photoradical generators also
By using various sensitizers in combination, sensitization of intrinsic sensitivity and spectral sensitivity can be performed. Representative sensitizers include, for example, "Sensitizer", edited by Katsumi Tokumaru and Shin Okawara, Kodansha 1
Compounds described on pages 64-75 of 987 can be mentioned.

As an example of the type 2, the compound which decomposes by light is a photo-free radical generator having an oxidizing power similar to the type 1, and an element which reacts with the decomposition product to form a color is:
Examples include couplers and aromatic primary amines. For example, the generation of an azomethine dye by the oxidative coupling of an aromatic primary amine such as N, N-diethyl-p-phenylenediamine or 4-aminoantipyrine with a phenol or an active methylene compound is described in silver halide photography. As is well known in the field of photosensitive materials, the above-mentioned free radicals can be used to cause an oxidative coupling reaction to generate a dye. As the aromatic primary amine that can be used, other than the above-mentioned amines,
p-aminophenol, N, N-diethyl-2-methyl-p-phenylenediamine, N-ethyl-N-methanesulfonylaminoethyl-2-methyl-p-phenylenediamine, N, N-didodecyl-p-phenylenediamine And the like. Further, the above-mentioned aromatic primary amine is
If necessary, it can be used in the form of hydrochloride, sulfate, tosylate, perfluoroalkyl sulfonate, and the like. In addition, an acyl form, for example, an acetyl form, a benzoyl form, a p-toluenesulfonyl form, a (2,4-di-t-pentyl-phenoxy) acetyl form, and a p-dodecyloxyphenylsulfonyl form can also be used.
Among these, preferred aromatic primary amines include aminoantipyrine and perfluoroalkylsulfonic acid salts of N, N-dialkylamino-p-phenylenediamine derivatives.

As the coupler which generates a dye by oxidative coupling with an aromatic primary amine, those known in the field of silver halide color photographic light-sensitive materials can be used. Examples of couplers that can be used include U.S. Pat.
772, 162, 2,895,826, 3,0
02,836, 3,034,893, 2,47
4,293, 2,423,730, 2,36
7,531, 3,041,236, 4,33
No. 3,999, No. 2,600,788, No. 2,36
9,869, 2,343,703, 2,31
1,082, 3,152,896, 3,51
9,429, 3,062,653, 2,90
8,573, 2,875,057, 2,40
7,210, 3,265,506, 2,29
8,443, 3,048,194, 3,44
No. 7,928 and Agfa Mitteilung
en's Farbkuppler-eine Liter
atureberesicht, Vol. III, 112-1
It is described in representative patents and publications, such as page 75 (1961). Among them, examples of preferable couplers include phenols, naphthols, pyrazolones, pyrazolotriazoles, acylacetanilides and the like. Both so-called 2-equivalent couplers in which a leaving group is substituted at the active site of the coupler and 4-equivalent couplers without active site substitution can be used. The reaction with the coupler may be accelerated by using a base, and a base may be used in combination as needed.
As the base, an organic base such as triphenylguanidine, trihexylamine, pyridine and quinoline, an inorganic base such as sodium hydrogen carbonate and potassium carbonate, a metal salt of an organic acid such as salicylic acid metal salt, and the like can be used.

Examples of the type 3 include a case where the compound decomposed by light is an aromatic azide and a component which reacts with the decomposition product to form a color is a coupler.
When an aromatic azide compound is decomposed by light, nitrene is generated. The produced nitrene can produce an azomethine dye by the reaction with the above-mentioned coupler. Examples of the aromatic azide compound that can be used include, for example, 4- (N,
N-diethylamino) phenylazide, 2,5-dibutoxy-4-morpholinophenylazide, 2,5-dibutoxy-4-phenylthiophenylazide, 4- (N-ethyl-N-methylsulfonylaminoethylamino) -2
-Methylphenyl azide, 4-diethylamino-3-dodecyloxycarbonylphenyl azide, 1-naphthyl azide, 2-naphthyl azide, anthranyl azide, 3
-Quinoline azide, 9-acridine azide and the like can be used. Examples of preferred aromatic azides include p-dialkylaminophenyl azides. Examples of the coupler that forms a dye by coupling with an azide include those described above.

In the photochromic element of the present invention, all the components of the element which develops a color by reacting with the compound decomposed by light and the decomposition product thereof are not uniformly mixed before heating. At least one component of the element that develops a color by reacting with the compound that decomposes by light and the decomposition product thereof,
It must be isolated by some means before heating. Such an isolation method requires isolation that does not cause a color reaction even if a compound decomposed by light is partially decomposed during storage.

As an available isolation method, for example, the components can be prevented from being uniformly mixed by solid dispersion or emulsification dispersion. Further, in order to more reliably perform isolation, components to be isolated during storage can be applied separately to another layer on the support. It is also effective to provide an intermediate layer between each layer. A more preferred form is to use microcapsules. Microcapsules preferred in the present invention,
At room temperature, the substance isolation action of the microcapsule wall prevents the contact of the substance inside and outside the capsule, and when heated at a certain temperature, the permeability of the substance increases. The permeability of the microcapsules by temperature depends on the capsule wall material, core material,
It can be controlled by changing the glass transition temperature of the capsule wall depending on the type of additive. Examples of the wall material of the microcapsules that can be used in the present invention include polyester, polycarbonate, polyurethane, polyurea, polyamide, polyether polycarbonate, urea-formaldehyde resin, melamine-formaldehyde resin, polystyrene, styrene-methacrylate copolymer, gelatin, and polyvinylpyrrolidone. And polyvinyl alcohol. A plurality of these wall materials may be used.

In the present invention, among the above-mentioned wall materials, polyurethane, polyurea, polyamide, polyester, polycarbonate and the like are preferable in terms of isolation, heat responsiveness and ease of production, and polyurea and polyurethane are particularly preferable. For details of microcapsules that can be preferably used in the present invention, see US Pat.
No. 6,696.

The microcapsules used in the present invention are prepared by emulsifying a core material containing a substance to be encapsulated, and then forming a polymer material wall around the oil droplets to form microcapsules by interfacial polymerization. The method is preferred. At that time, it is preferable to use an organic solvent to form emulsified oil droplets as necessary, and the organic solvent to be used can generally be appropriately selected from high-boiling organic solvents. For example, phosphates, phthalates, acrylates, methacrylates and other carboxylic esters, aliphatic amides, alkylated biphenyls,
Alkylated terphenyl, chlorinated paraffin, alkylated naphthalene, diarylethane and the like are used. Specifically, JP-A-60-242094 and JP-A-62-7
No. 5409 can be used. In addition to the above-mentioned high-boiling organic solvents, low-boiling solvents such as ethyl acetate and methylene chloride can be used in combination as solubilizers. On the other hand, the water layer mixed with the oil layer can contain a water-soluble polymer as a protective colloid, and for example, polyvinyl alcohol, gelatin, and a cellulose derivative can be used. When emulsifying and dispersing, an appropriate surfactant can be selected from known surfactants to prevent precipitation and aggregation. Other color-forming elements to be provided outside the microcapsules may be dispersed by any of solid dispersion and emulsion dispersion.

Further, in the photochromic element of the present invention, the compound decomposed by light is heated and reacts with the decomposition product to cause a color reaction at a site mixed with the element which forms a color. That is, at a site separated from an element that develops a color by reacting with a decomposition product, no color development reaction occurs even when irradiated with light. Preferably, when the non-heated portion is exposed to light, the compound that decomposes by light decomposes and changes into a substantially harmless compound by reacting with the surrounding compounds without participating in the color-forming reaction.

In the photochromic element of the present invention, the amount of the compound decomposed by light and the element which forms a color by reacting with the decomposition product thereof is not particularly limited. Is selected in consideration of the film thickness, coloring efficiency, coloring density, and the like.

The preferred use amount of each component is 4 × 10
⁻⁴ mol / m ^{2 to} 2 × 10 ⁻² mol / m ² .
Further, the film thickness when coated on the support is not particularly limited, but in consideration of heat sensitivity and image sharpness, the dry film thickness is 0.5 μm to 50 μm.
m is preferable, and more preferably in the range of 1 μm to 20 μm.

As the light decoloring element of the present invention, any element can be used as long as it is mixed by heat to form a latent image, and the latent image or the image other than the latent image is decolorized by light. .

First, an element which forms a latent image by being mixed by heat and which erases the latent image (hereinafter referred to as a negative type optical decoloring element) will be described. The negative-type photobleachable element of the present invention comprises:
Preferably, it is composed of a compound that decomposes by light and a dye that decolorizes by reacting with its decomposition product. A more specific embodiment of the negative-acting photobleachable element of the present invention is where the compound that decomposes by light is a photoradical generator, initially with the photoradical generator and dye separated. When heat is applied, the photo-free radical generator and the dye are mixed to form a latent image.Subsequently, the latent image is irradiated with light absorbed by the photo-free radical generator. Is decolorized to be substantially colorless, while the photo-radical generating agent and the dye are not in a mixed state except for the latent image, so that free radicals do not react with the dye and do not decolor the dye. In this manner, the dye disappears in the heated recording portion and remains in the non-heated recording portion, so that a negative image is formed with respect to the recorded image.

Next, an element which forms a latent image by being mixed by heat and erases a color other than the latent image (hereinafter referred to as a positive type optical decoloring element) will be described. The positive-type photobleaching element of the present invention comprises:
Preferably, it is composed of a compound that decomposes by light, a dye that decolorizes by reacting with its decomposition product, and a compound that suppresses the reaction by which the decomposition product decolorizes the dye (hereinafter, decolorization inhibitor). . A more specific embodiment of the positive-type photobleachable element of the present invention is where the compound decomposed by light is a photoradical generator, wherein the photoradical generator and the dye are initially mixed and These and the decolorizing inhibitor are separated from each other, and by heating, the three components of the photo-free radical generator, the dye and the decolorizing inhibitor are mixed to form a latent image, and subsequently the photo-free radical is formed. By irradiating the light absorbed by the generator, free radicals are generated in the latent image, but the colorlessization of the dye is suppressed due to the presence of the decolorizing inhibitor, and the colorlessness of the dye does not occur, whereas in the other than the latent image The generated free radicals cause the dye to be decolorized to a substantially colorless one. In this manner, the dye remains in the heated recording portion and the dye disappears in the non-heated recording portion, so that a positive image is formed with respect to the recorded image.

The dye and the photo-radical generator used in the photo-decolorizable element of the present invention are capable of decoloring when irradiated with light absorbed by a photo-radical generator, that is, substantially in the visible light region. It can be used in a combination of a dye and a photo-free radical generator that can be converted into a compound that does not absorb light.

Examples of the dye include an azo dye, an azomethine dye, a polyene dye, a polymethine dye, a quinone dye, an indigo dye, a diphenylmethane dye, a triphenylmethane dye, and a phthalocyanine dye. Specific examples include dyes described in "Dye Handbook", edited by Japan Color Materials Association, Kodansha. From among these, a selection can be made in consideration of the color tone, light decoloring property, fastness, cost, and the like. Among them, an azomethine dye is mentioned as a preferable dye. In particular, from the viewpoint of color tone and fastness, azomethine dyes used in conventional color photography, specifically, acylacetanilide derivatives, pyrazolone derivatives, pyrazolotriazole derivatives,
An azomethine dye obtained by an oxidative coupling reaction between a coupler such as a phenol derivative or a naphthol derivative and a color developing agent (p-phenylenediamine derivative) is preferred. Examples of preferred dyes are shown below, but are not limited thereto.

[0039]

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[0040]

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[0041]

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[0042]

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The photo-radical generating agent in the photo-decolorizing element of the present invention is activated and absorbs light of a specific wavelength to decolor the dye. And those that extract hydrogen free radicals and the like from other molecules when activated by absorbing light, and the compounds themselves that absorb light and the molecules from which hydrogen and the like are extracted become free radicals. Further, as the light absorbed when generating free radicals, light absorbed by dyes called so-called sensitizers can be used. However, in this case, the dye serving as a sensitizer preferably has no absorption in the visible region, and does not affect the image. Specific examples of the photo-radical generator include, for example, JP-B-62-39728 and JP-B-63-39728.
Azide compounds such as 2,4,6-triarylimidazole dimer compound described in US Pat. No. 2099, 2-azidobenzoxadiazole, benzoylazide and 2-azidobenzimidazole described in US Pat. No. 3,282,693 Pyridium compounds such as 3'-ethyl-1-methoxy-2-pyridothiocyanine perchlorate and 1-methoxy-2-methylpyridinium-p-toluenesulfonate described in U.S. Pat. No. 3,615,568; Bromosuccinimide, tribromomethylphenylsulfone, diphenyliodonium salt, 2-trichloromethyl-5- (p-butoxystyryl) -1,3,4-oxadiazole, 2,6-bis (trichloromethyl) -4-
Organic halogen compounds such as (p-methoxyphenyl) -s-triazine, carbonyl compounds such as benzophenone, thioxanthone, anthraquinone and benzoin ether; azo compounds such as azobisisobutyronitrile; organic sulfur compounds such as alkyl disulfide and mercaptan;
And diazo compounds. The wavelength of the light for activating the photoradical generator can be selected in consideration of the ease of handling as a recording material, the availability of the light source to be used, and the cost. The ease of handling as a recording material may be limited, for example, if the photosensitive material is sensitively exposed to light having a wavelength similar to that of room light, because it has a problem in stability and must be handled in a dark room. In order to avoid such restrictions, it is preferable to use a region from ultraviolet to a part of visible light or infrared light. Among them, taking into account the strength of energy and the availability of light sources, etc.
It is preferable to use light in the range of nm to 450 nm. Preferred photo-radical generators include carbonyl compounds such as anthraquinone and benzoin ether, and diazo compounds. In addition, it is preferable that the spectral absorption maximum wavelength of the photo-free radical generator is also in the range of 250 nm to 450 nm from the viewpoint of photo-radical generation efficiency and the like. Examples of preferred photo-radical generators are shown below, but are not limited thereto.

[0044]

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[0045]

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In the photo-decoloring element of the present invention, the decoloring inhibitor inhibits the reaction between the photo-free radical generator and the dye, thereby suppressing the decoloring. The mechanism of the decolorization suppression is unclear, but it is possible to capture the photoradicals generated when the photoradical generator is activated, or to recolor the decolored body by the reaction between the dye and the active photoradical generator. It is considered that the mechanism for causing the decolorization is caused by the combination of the photo-free radical generator and the decoloration inhibitor. Examples of the decoloration inhibitor used in the present invention include guanidines such as triphenylguanidine, tetramethylguanidine, dicyclohexylguanidine, bis (2-ethylhexyl) amine, trioctylamine, diisopropylethylamine, N, N-dimethyldodecylamine , Piperazine, pyrrolidine, amines such as hindered amine,
2,5-di-ter-octylhydroquinone, 2,5
Hydroquinone derivatives such as -di-sec-dodecylhydroquinone, p-dodecyloxythiophenol, 2-
Mercaptans such as mercaptobenzimidazole and 2-mercaptobenzothiazole, 2,6-di-ter-
Butylphenol, 4,4'-butylidenebis (6-t
er-butyl-m-cresol), phenols such as hindered phenol, hydrazines, reducing agents such as phenidone and ascorbic acid, but are not limited thereto. Among these, preferred color erasure inhibitors include guanidines, amines, and phenols. Preferred examples of the decolorization inhibitor are shown below, but are not limited thereto.

[0047]

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In the photo-decoloring element of the present invention, the amounts of the dye, photo-free radical generator and decoloring inhibitor used are not particularly limited, but the film thickness when coated on a support, The selection is made in consideration of the decoloring suppression efficiency, the color density, and the like.
The amount of the dye used is preferably 1 × 10 ⁻⁵ mol / m ² to 1
× 10 ^-2 mol / m ² , more preferably 5
The range is from × 10 ⁻⁵ mol / m ² to 1 × 10 ⁻³ mol / m ² . The amount of the photo-free radical generator used is preferably 0.
It is in the range of 5 to 50 times mol, and more preferably in the range of 1.0 to 10 times mol of the dye. The use amount of the decolorization inhibitor is preferably in the range of 0.1 to 100 times mol of the photo-free radical generator, more preferably 1 to 30 times the photo-free radical generator.
The range is twice as high. Further, the film thickness when coated on the support is not particularly limited, but in consideration of heat sensitivity and image sharpness, the dry film thickness is preferably in the range of 0.5 μm to 50 μm. Preferably, 1 μm to 20
More preferably, it is in the range of μm.

In the photo-decolorizable element of the present invention, the dye and the photo-free radical generator are separated in the negative type, and the dye and the photo-free radical generator are mixed in the positive type. Are isolated. Available quarantine methods include:
The same methods as those mentioned as the isolation method in the photochromic element can be used, and among them, the method using microcapsules is preferred in terms of the degree of isolation, the reactivity of coloring and decoloring, the raw preservability, and the like. Most preferred. As for the wall material of the microcapsule, the preparation method, and the solvent, the same materials as described in the description of the photochromic element can be used.

In the multicolor recording material of the present invention, when a latent image is formed by mixing with heat and a light decoloring element of a type in which a color other than the latent image is decolorized by light is used, the resulting image is obtained. Is positive for the thermal image, which is preferable in that the apparatus and software can be simplified.

The multicolor recording material of the present invention can be prepared by coating a photochromic element and a photodecolorable element on a support. At this time, as a binder of the dispersion, polyvinyl alcohol, gelatin, styrene-butadiene latex, carboxymethyl cellulose, gum arabic,
Various emulsions such as polyvinylpyrrolidone, polyvinyl acetate and polyacrylate can be used, and the amount used is 0.5 g / m ^{2 to} 5 g / m ² in terms of solid content.
m ² .

In the multicolor recording material of the present invention, it is preferable to provide a protective layer in consideration of image protection, prevention of adhesion between recording materials, prevention of adhesion to a thermal head, brushability, smoothness, and the like. As the binder for the protective layer, a known binder can be used. For example, methylcellulose, carboxymethylcellulose, hydroxymethylcellulose, starches, gelatin, gum arabic, casein, styrene-maleic anhydride copolymer hydrolysate, polyvinyl alcohol, carboxy-modified polyvinyl alcohol, polyacrylamide derivatives, polyvinylpyrrolidone, sodium polystyreneate , Sodium alginate, styrene-butadiene latex, acrylonitrile-butadiene rubber latex, polymers such as polyvinyl acetate emulsion, silicone resin, melamine resin,
A binder such as phenol resin, acrylic resin, polyester resin, epoxy resin, fluororesin, nitrocellulose, cellulose acetate propionate, cellulose acetate, fluorinated vinylidene resin, and chlorinated rubber can be used. As fillers for the protective layer, zinc oxide, calcium carbonate, barium sulfate, titanium oxide, lithobon,
Inorganic pigments such as talc, limestone, kaolin, aluminum hydroxide, amorphous silica, colloidal silica, polystyrene, polymethyl methacrylate, polyethylene, vinyl acetate resin, vinyl sulfide resin, vinylidene sulfide resin, styrene-methacrylate copolymer, Organic pigments such as vinylidene chloride, polyurea, and melamine-formaldehyde; metal soaps such as zinc stearate, calcium stearate, and aluminum stearate; and paraffin wax, microcrystalline wax, carnauba wax, methylol stearylloamide, polyethylene wax, and silicone. Waxes can be added. These fillers may be used alone or in combination of two or more.

When the multicolor recording material of the present invention is applied on a support such as paper or a synthetic resin film, a generally well-known coating method can be used. For example, it can be applied by a dip coating method, an air knife coating method, a curtain coating method, a roller coating method, a doctor coating method, a wire bar coating method, a slide coating method, a gravure coating method, a spin coating method or an extrusion coating method. it can.

Examples of the support that can be used in the multicolor recording material of the present invention include papers, films such as regenerated cellulose, cellulose acetate, cellulose nitrate, polyethylene terephthalate, polyethylene, polyvinyl acetate, and polyethylene naphthalate, glass, and the like. Wood, metal and the like.

As the light source that can be used in the present invention, various light sources that emit light having a wavelength capable of decomposing a compound decomposed by light can be used. For example, various fluorescent lamps, mercury lamps of various pressures, halogen lamps, xenon lamps, A tungsten lamp or the like can be used. Further, in the present invention, the wavelength of light for forming the first and second latent images is controlled by a method using light sources having different main emission wavelengths, a method of cutting unnecessary wavelengths by an optical filter, or the like. be able to.

In the present invention, the control of the thermal energy applied to the recording layer containing the photochromic element and the recording layer containing the photodecolorable element can be performed, for example, by changing the electric energy applied to the thermal head. it can. Specifically, this is performed by changing the voltage applied to the thermal head or by changing the time for applying the voltage. The latter is more general. Further, an infrared absorbing dye, carbon black, or the like may be added to a recording material, and heating recording by infrared laser light may be performed.

[0057]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. “Parts” indicating the amount of addition indicates “parts by weight”.

Example 1 Preparation of Capsule Solution A 1.5 parts of Dye D-1 and 3 parts of a photo-free radical generator P-13 were dissolved in 10 parts of ethyl acetate and 10 parts of 1-phenyl-1-xylylethane. 8.0 parts of a xylylene diisocyanate / trimethylolpropane adduct were added. This solution was added to 60 parts of a 6% aqueous solution of polyvinyl alcohol, and emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle diameter of 1 μm. 20 parts of water was added to the obtained emulsion, and stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain capsule liquid A.

Preparation of Discoloration Inhibitor Solid Dispersion 30 parts of the decolorization inhibitor I-2 was added to 150 parts of a 4% aqueous solution of polyvinyl alcohol, and dispersed by a sand mill. A dispersion was obtained.

Preparation of Coating Solution A for Positive-Type Optical Decoloring Layer The coating solution A was obtained by mixing 5 parts of the capsule solution A and 4 parts of the solid dispersion of the decolorizing inhibitor.

Preparation of Capsule Solution B 2,5-Dibutoxy-4-morpholinophenylazide 6
Was dissolved in 5 parts of ethyl acetate and 10 parts of diisopropylnaphthalene, and 20 parts of tolylene diisocyanate / trimethylolpropane adduct was added. This solution was added to 46 parts of an aqueous 8% phthalated gelatin solution, and 18 parts of water and 1 part of water were added.
Two parts of a 0% sodium dodecylbenzenesulfonate aqueous solution was added, and the mixture was emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. Water 20 was added to the obtained emulsion.
And stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain capsule liquid B.

Preparation of coupler dispersion B 4 parts of 7-chloro-6-tert-butyl-3- (3-dodecylsulfonylpropyl) pyrazolo [3,2-c] triazole was dissolved in 1 part of tricresyl phosphate. ,
32 parts of a 15% aqueous gelatin solution, 5 parts of a 10% aqueous sodium dodecylbenzenesulfonate solution and 30 parts of water were added, and the mixture was ultrasonically dispersed to obtain a coupler dispersion B.

Preparation of coating solution B for photochromic layer 6 parts of the above capsule liquid B, 8 parts of the above coupler dispersion B,
A coating solution B was obtained by mixing 2 parts of a 5% gelatin aqueous solution and 4.5 parts of water.

Preparation of Recording Paper of the Present Invention Coating solution B for photochromic layer was coated on wood free paper with a wire bar so that the coating amount of azide in coating solution B was 0.15 g / m ² and dried. A first recording layer was formed. A coating solution A of a positive-type photo-decoloring layer is applied thereon with a wire bar so that the reflection density of the red portion becomes approximately 1.0, and dried to form a second recording layer. I got

Example 2 Preparation of Capsule Solution C 1.5 parts of dye D-1 was dissolved in 10 parts of ethyl acetate and 10 parts of 1-phenyl-1-xylylethane, and xylylene diisocyanate / trimethylolpropane adduct was added. 0
Parts were added. This solution was added to 60 parts of an aqueous solution of 6% polyvinyl alcohol, and emulsified and dispersed at 20 ° C. using a homogenizer.
And stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain capsule liquid C.

Preparation of solid dispersion of photo-radical generating agent 9 parts of P-13 was added to a 4% aqueous solution of polyvinyl alcohol 15
0 parts, dispersed in a sand mill, and average particle size 1 μm
Was obtained.

Preparation of Coating Solution C for Negative-Type Photo-Decoloring Layer Coating solution C was obtained by mixing 5 parts of the above-mentioned capsule solution C and 4 parts of the above-mentioned photo-radical generator solid dispersion.

Preparation of Recording Paper of the Present Invention Coating solution B for photochromic layer was coated on wood free paper with a wire bar such that the coating amount of azide in coating solution B was 0.15 g / m ² and dried. A first recording layer was formed. A negative type photo-decoloring layer coating solution C is applied thereon with a wire bar so that the reflection density of the red portion becomes approximately 1.0, and dried to form a second recording layer. I got

Comparative Example 1 Preparation of Capsule Solution D 3.4 parts of PF ₆ salt of 2,5-dibutyloxy-4-morpholino-benzenediazonium, 10 parts of ethyl acetate,
-Phenyl-1-xylylethane was dissolved in 10 parts, and xylylene diisocyanate / trimethylolpropane adduct 8.0 parts was added. This solution was added to 60 parts of a 6% aqueous solution of polyvinyl alcohol, and emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle diameter of 1 μm. 20 parts of water was added to the obtained emulsion, and stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain a capsule liquid D.

Preparation of Coupler Dispersion D 2-Chloro-5- [3- (2,5-di-t-amylphenoxybutanoylamino)] pivaloylacetamide 1
4 parts, triphenylguanidine 6 parts, tricresyl phosphate 10 parts and ethyl acetate 20 parts are uniformly mixed,
This solution was added to 170 parts of a 4% by weight aqueous solution of polyvinyl alcohol, mixed, and emulsified and dispersed at 20 ° C. to obtain a coupler dispersion D.

Preparation of Coating Solution D for Diazo-Type Photosensitive and Heat-Sensitive Layer Coating solution D was prepared by mixing 6 parts of capsule solution D, 5.5 parts of coupler dispersion D, and 0.5 part of a 20% aqueous solution of calcium chloride.

Preparation of Capsule Solution E 0.41 part of an organic boron compound anion salt of the following organic cationic dye compound, 0.08 part of tetramethylammonium tetrabutyl borate, 12 parts of methyl isobutyl ketone
Was dissolved in 5 parts of ethyl acetate and 10 parts of diisopropylnaphthalene, and 20 parts of tolylene diisocyanate / trimethylolpropane adduct was added. This solution was added to 46 parts of an aqueous 8% phthalated gelatin solution, and 18 parts of water and 1 part of water were added.
Two parts of a 0% sodium dodecylbenzenesulfonate aqueous solution was added, and the mixture was emulsified and dispersed at 20 ° C. using a homogenizer to obtain an emulsion having an average particle size of 1 μm. Water 20 was added to the obtained emulsion.
And stirring was continued at 40 ° C. for 3 hours. Thereafter, the temperature was returned to room temperature to obtain a capsule solution E.

[0073]

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Preparation of fixing agent solid dispersion 30 parts of benzyl 4-hydroxybenzoate was added to 150 parts of a 4% aqueous solution of polyvinyl alcohol and dispersed by a sand mill to obtain a fixing agent solid dispersion having an average particle diameter of 1 μm. .

Preparation of Coating Solution E for Organic Boron Salt Type Photodecoloring Layer Next, the above-mentioned capsule solution E / fixing agent dispersion was mixed in a weight ratio of 1 /
The coating liquid E was prepared by mixing so as to be 1.

Preparation of Comparative Recording Paper An organic boron salt type photo-decoloring layer coating solution E was applied on a high-quality paper with a wire bar so that the reflection density of the red portion became approximately 1.0, and dried. Was formed. A diazo-type photosensitive and heat-sensitive layer coating solution D is coated thereon with a wire bar such that the coating amount of diazo in the coating solution D is 0.15 g / m ² .
After drying, a second recording layer was formed to obtain a comparative recording paper.

The recording paper of Example 1 was heated at 90 ° C. for 5 seconds (0.5 kg) using a thermal gradient tester (manufactured by Toyo Seiki).
/ M ² ) After heating, the entire surface was illuminated with a high-pressure mercury lamp for 10 seconds using a filter that cuts light of 400 nm or less. It has disappeared. Next, the decolored part was heated at 110 ° C. for 5 seconds using a thermal gradient tester,
When the entire surface was irradiated with a high-pressure mercury lamp for 10 seconds using a filter that cuts light of nm or more, the heated portion developed a magenta color.

Further, the recording paper of Example 2 was heated at 90 ° C. for 5 seconds (0. 0 ° C.) using a thermal gradient tester (manufactured by Toyo Seiki).
5 kg / m ² ) After heating, the entire surface was illuminated with a high-pressure mercury lamp for 10 seconds using a filter that cuts light of 400 nm or less. And remained. Next, the decolored part was heated at 110 ° C. for 5 seconds using a thermal gradient tester,
When the entire surface was irradiated with a high-pressure mercury lamp for 10 seconds using a filter that cuts light of 400 nm or more, the heated portion developed magenta.

Further, the recording paper of the comparative example was heated at 90 ° C. for 5 seconds (0.5 seconds) using a thermal gradient tester (manufactured by Toyo Seiki).
kg / m ² ) When heated, the heated portion developed yellow. Next, use Recopy Super Dry 100
The yellow image was fixed by irradiating light for 2 seconds. Next, the above-mentioned non-heated part was heated at 110 ° C. for 5 seconds using a thermal gradient tester, and irradiated with light for 10 seconds with a fluorescent lamp. In the part, the color of magenta disappeared.

The recording papers of Examples 1 and 2 and Comparative Example were stored for 3 days under conditions of high temperature and high humidity (50 ° C., 80%) before recording, and then the same operation as above was performed.

Table 1 shows the results of measuring the reflection densities of the respective hues of the obtained samples in the heated part and the non-heated part.

[0082]

[Table 1]

[0083]

As is clear from the examples, by using the recording material of the present invention, even if stored for a long period of time, there is no decrease in the maximum color density and no fogging, good color reproducibility,
A multicolor recorded image having image fastness was obtained.

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Osamu Hatano 1st Konica Corporation, Sakuracho, Hino-shi, Tokyo In-house (72) Inventor Kenzo Nakazawa 1st Konica Corporation, Sakuracho, Hino-shi, Tokyo In-house

Claims (4)

[Claims] 1. A multicolor recording material comprising a support and a first recording layer containing a photochromic element and a second recording layer containing a photodecolorable element, wherein the first recording layer The latent image is formed by mixing the light-coloring elements by heat to form a latent image, and the latent image is colored by light.The latent image is formed by mixing the light-decoloring elements by heat in the second recording layer. A multicolor recording material formed, wherein the latent image or an image other than the latent image is erased by light. 2. The method according to claim 1, wherein the light decoloring elements of the second recording layer are mixed by heat to form a latent image, and a color other than the latent image is decolorized by light. The multicolor recording material as described. 3. The multicolor recording material according to claim 1, wherein the light-color-forming element comprises a compound which is decomposed by light and an element which forms a color by reacting with a decomposition product thereof. 4. The multicolor recording according to claim 1, wherein the photo-decolorizable element comprises a photo-free radical generator and a dye which is decolorized by the free radical generated by the photo-free radical generator. material.